This invention relates to compositions, methods of treatment and articles of manufacture, wherein there is employed an antimicrobial superabsorbent formed of a cross-linked hydrophilic sodium salt form of a partially neutralized acrylic acid-based polymer gel having covalently bonded thereto a silane, for the purpose of providing the benefits of odor reduction, control of microbes, and reduction of microbial rashes and allergies.
Antimicrobial agents are chemical compositions that are used to prevent microbiological contamination and deterioration of products, materials, and systems. Particular areas of application of antimicrobial agents and compositions are, for example, cosmetics, disinfectants, sanitizers, wood preservation, food, animal feed, cooling water, metalworking fluids, hospital and medical uses, plastics and resins, petroleum, pulp and paper, textiles, latex, adhesives, leather and hides, and paint slurries. Of the diverse categories of antimicrobial agents and compositions, quaternary ammonium compounds represent one of the largest of the classes of antimicrobial agents in use. At low concentrations, quaternary ammonium type antimicrobial agents are bacteriostatic, fungistatic, algistatic, sporostatic, and tuberculostatic. At medium concentrations they are bactericidal, fungicidal, algicidal, and viricidal against lipophilic viruses. Silicone quaternary ammonium salt compounds are well known as exemplified by U.S. Pat. No. 3,560,385, and the use of such compounds as antimicrobial agents is taught, for example, in a wide variety of patents such as U.S. Pat. Nos. 3,730,701, and 3,817,739, where the compounds are used to inhibit algae; 3,794,736; 3,860,709; 3,865,728, where the compounds are used to treat aquarium filters; 4,259,103; and in British Patent No. 1,386,876. Published unexamined European Application No. 228464 of July 15, 1987, teaches that microorganisms on plants can be killed by the application thereto of an aqueous mixture of a surfactant and an organosilicon quaternary ammonium compound. In a particular application of an antimicrobial silicone quaternary ammonium compound, a paper substrate is rendered resistant to the growth of microorganisms in U.S. Pat. No. 4,282,366. In U.S. Pat. No. 4,504,541, an antimicrobial fabric is disclosed which is resistant to discoloration and yellowing by treatment of the fabric with a quaternary ammonium base containing an organosilicone. U.S. Pat. No. 4,615,937, as well as its companion U.S. Pat. No. 4,692,374, relate to wet wiper towelettes having an antimicrobial agent substantive to the fibers of the web and being an organosilicon quaternary ammonium compound. Thus, the versatility of such compositions is readily apparent.
Absorbent polymers capable of absorbing from about thirty to sixty grams of water per gram of polymer are known, as is the use of such polymers in disposable diapers, sanitary napkins, surgical pads, and bath mats, for example. particularly sought-after property is increased water absorbency. Polymers having this property often are referred to as hydrogels or superabsorbents. The nature and utility of superabsorbents are illustrated by U.S. Pat. No. 4,449,977. According to this reference, a desirable feature of a superabsorbent is the presence of acrylate or methacrylate groups which can be salts, amides, esters, or the free acids. Many hydrogels are based on acrylate and methacrylate polymers and copolymers, for example, as shown in U.S. Pat. Nos. 2,976,576, 3,220,960, 3,993,616, 4,154,898, 4,167,464, 4,192,727, 4,192,827, and 4,529,739. Hydrogels based on starch or a modified starch are shown by U.S. Pat. Nos. 4,069,177, 4,076,663, 4,115,332, and 4,117,222. Other hydrogels are based on poly(oxyalkylene) glycols as in U.S. Pat. No. 3,783,872. Hydrogels prepared from hydrolyzed crosslinked polyacrylamides and crosslinked sulfonated polystyrenes are described in U.S. Pat. No. 4,235,237. Finally, polymers based on maleic anhydride have been described in U.S. Pat. Nos. 2,988,539, 3,393,168, 3,514,419, 3,557,067, and 4,401,793. U.S. Pat. No. 3,900,378 describes hydrogels from radiation crosslinked blends of hydrophilic polymers and fillers. Such category of absorbent polymers preferred in the present invention, however, can be exemplified by, for example, U.S. Pat. No. 3,966,679, which relates to acrylic acid based water swellable super absorbent polymers useful as catamenial tampons and diapers. Such absorbent polymers that possess, in addition to their superabsorbency characteristics, the property of antimicrobial activity, are not known, however. Therefore, in accordance with the present invention, it has been found that superabsorbent compositions which have antimicrobial properties can be formed, which possess the characteristics and advantages of both categories of the silicone quaternary ammonium salts as well as the acrylic acid based water swellable super absorbent polymer compositions noted above. Thus, in addition to absorbing large quantities of fluids, the compositions of the present invention act in preventing microbiological contamination and deterioration of products, materials, and systems. For example, 3-(trimethoxysilyl)propyldimethyloctadecylammonium chloride, hereinafter referred to as TMS, is an effective antimicrobial agent in which the active ingredient hydrolyzes in water and reacts with substrates with which it is brought into contact. These substrates demonstrate nonleaching broad spectrum antimicrobial activity. By including an antimicrobial component in the water swellable absorbent composition, the benefits of both compositions are realized as against both functioning independently one from the other. Hence, the compositions set forth in the present invention possess unique features and advantages over existing antimicrobial treating agents and hydrophilic gels and provide improved results thereover. Thus, the disadvantages of the prior art are overcome with the present invention wherein improved antimicrobial agents are provided.